I would not recommend to forget any kind of investment. This is one of the reason why many people missed out on profit in altcoin. Although Bitcoin is believed to be ever rallying even with dips, it still ends up breaking its ATH, forgetting our Bitcoin investment may make us not to remember it. Instead, we should be firm with our beliefs and keep on holding while we keep ourselves updated on current events. We never know what the future of Bitcoin is, so the possibility of the Bitcoin market crashing and never recovering may happen. If this happens we will end up missing the opportunity to sell at a profit.
Investing in altcoins could be really good for the short term. However, if you're looking to invest for the long term with the potential for higher profits, the right thing to do is to invest in Bitcoin and just wait. I believe that Bitcoin's price will increase a lot in the future and reach a new ATH in the next few years, probably 1-2 years after the halving. I do recommend investing in both, for the long term when it comes to Bitcoin and for the short term when it comes to investing in altcoins. 